2010 - Sudden 12V Battery Failure

I keep a voltmeter plugged into a 12V socket, and the system's pretty rigorous about maintaining the voltage at 14.4V. The only time it ever drops is when the car is shut off. I believe the Dodge Ram was invariably at 14.2 V.

 

The Dodge truck has a huge battery, relatively speaking, so a little extra voltage won't hurt it at all.

Your readings in the Prius indicate that the 12 V battery is never REALLY getting fully charged despite what you may think.
That is not necessarily a bad thing since it probably is close.

A couple of technical clarifications: If the charger voltage read 14.2, then the charging current was not really zero; just too small for the built-in meter to register. And this is evidence that your charger is not automatic as 14.2 is at least a half a volt too high for proper long term float.

 

Size is irrelevant. As you say, if the battery is periodically tested, and the correct amount of charge is applied, it can last a long time. That's exactly what a battery-tender does. If you can find a different voltage at the battery terminals than in the rest of the 12V system, please let us know.

 

The only thing here truly irrelevant is YOU.

Heavy, thick plates that are spaced widely apart can be exposed to higher charging and float voltages without damage.
A smaller battery with closely spaced thin plates won't tolerate over-voltage charging nearly as well.

 

That's a reach.

 

Engineering is an art of balancing a lot of different variables to make the best doohickey for some purpose, within a set of constraints (like cost, size, design time, etc.). There's no reason to sacrifice all other variables (including quality and longevity) to maximize the one thing you're interested in (non-volatility).

You still didn't explain exactly *what* you want to be non-volatile, anyway. Maybe I'd even agree with you there. (i.e. radio station presets: That'd be a fantastic thing to drop in a non-volatile memory. Bluetooth pairings too. On the other hand, the frame buffers that hold what is currently on the Nav system's display – as well as the space that it uses as it is drawing the next frame to be displayed – would be a TERRIBLE thing to put in non-volatile memory.)

On the other hand, given that we don't have the equipment (software, connectors, hardware, firmware images, etc.) to re-flash and reset the many computers in our cars, perhaps it's a good thing for DIYers that simply disconnecting the 12V battery can be enough to fix some transient faults.

 

You forgot to mention how patents force auto-manufacturers to buy the B-grade engineering from companies who are marketing their own A-grade stuff.

 

i never thought of this. i checked my almost 3 year old battery after opening the drivers door and got 12.7, i'll try the release the hood trick tonight to see if it's different tomorrow.

 

If it does, it won't be a significant "improvement".
You do realize that you need to wait a while after the charger is removed before you can get an accurate reading, right ??

 

These batteries can last a long time!!!

From what I have read on this forum the date code is formatted as DD/MM/YY. If that's the case, the battery I am using right now is 11 years old!! The car is a 2004 Prius with 101000 miles on it. Is that right???

Date code is 120504W

 

wouldn't surprise me. the '04's were especially good. but the secret is not to let them run down by leaving a light on etc. once they run down, it substantially shortens the life.

 

There's no reason why a battery can't last that long if it's not exposed to large changes in charge-level. That means it hasn't been used to crank an engine (as in all Prius models) and it probably hasn't been deeply discharged to any great extent either. The capacity may be reduced after 11 years, but so-what? It doesn't have much to do, except to boot the computer, and to run accessories when the system is off.

I've seen plenty of mythology in here, like charging or replacing your battery to increase "performance." What performance? The Prius aux battery has a very easy job, and it doesn't have to be in very good condition to do it. These myths are being helped by advice from a few Toyota "experts," who aren't always free-and-clear from a conflict of interest where battery replacements are concerned.

 

Your selective memory has kicked in again; what you remember is twisted a bit.

NOBODY ever said to mess with the battery to "increase performance".

What they did say is that a weak failing battery can cause trouble with all kinds of things including engine performance.
Charging or replacing the battery can fix some performance PROBLEMS but that is quite different than what you said here.

 

Welcome back.
Where's my can of dog-spray again?

 

REALLY ???
What is this, if you can't come up with something intelligent to say you resort to an insult ??
It is getting really OLD.

 

Really? First time I've used that one.